1. Field of the Invention
This invention relates to a roller chain wear gauge and, more particularly, to a collapsible type gauge in which the gauge members are stored within the handle of the gauge.
2. Description of the Prior Art
Roller chain wear is a maintenance problem that is compounded by the nature of drive chain design, in that it is nearly impossible to determine whether a chain is excessively worn or good by appearance alone. The actual wear is incurred between the hardened pin and bushing surfaces, resulting in a "stretch" or elongation of the link spacing. When the elongation exceeds the operating tolerances of a drive chain assembly, several effects become noticeable. The first indication of wear is the resulting poor fit on the sprockets. A bad chain can quickly wear out sprocket teeth, causing a rounding or cupping of one side of the sprocket assembly. Further slack is then introduced into the power drive system, causing uneven power transfers, additional vibration, frictional heat and a general overall reduction of operating efficiency.
Roller chain wear inspection procedures typically require the user to measure the link spacing with a ruled measuring edge. This method has its shortcomings, as the inspection can only be performed to the nearest 32nd or 64th of an inch. The actual tolerance is often within thousandths of an inch, and the error introduced through the use of ruled edges can be sufficient to reach an improper conclusion concerning chain wear.